The modern mobile communication increasingly directs to provide multimedia service with high rate transmission to users, as shown in FIG. 1, a system architecture view of a system architecture evolution (SAE) is provided, wherein:
An user equipment (UE) 101 is a terminal unit for receiving data. An evolution universal terrestrial radio access network (E-UTRAN) 102 is a radio access network, including a macro base station (eNodeB/NodeB) that provides a wireless network interface for the UE. A mobile management entity (MME) 103 is responsible for managing movement context, conversation context and security information of the UE. A service gateway (SGW) 104 mainly provides a function as a user plane. MME 103 and SGW 104 are possibly located in the same physical entity. A packet data network gateway (PGW) 105 is responsible for a function, such as charging and lawful interception, and also can be located in the same physical entity with the SGW 104. A policy and charging rules function entity (PCRF) 106 provides a policy for quality of service (QoS) and charging standards. A universal packet radio service support node (SGSN) 108 is a network node equipment providing a route for data transmission in a universal mobile telecommunication system (UMTS). A home subscriber server (HSS) 109 is a home subsystem of the UE in charge of protecting user's information such as current position of the user equipment, address of the service node, user's security information and packet date context of the user equipment.
At present, sustainable development is a long-term target, so that people try to reduce resource waste and environmental damage as much as possible. For this, improving energy utilization efficiency and reducing energy consumption become more and more important. In a communication field, effort can be provided to study how to reduce the energy consumption and maintenance cost of the network equipment. The mobile operator endeavors in reducing the energy consumption and maintenance cost of the equipment as much as possible without interference to the present network. Wherein, how to improve the energy efficiency of the equipment and terminal is becoming a key point of reducing cost.
In the same region as shown in FIG. 2, multiple cellulars are repeatedly covered, and a cell B, cell C, cell D and cell E of LTE are completely covered by the cell A which may be a UMTS or GSM cell or a LTE cellular. The cell A provides a basic wireless coverage for this region, and is a cell as initially constructed. As the user capacity is increasing, the users in some districts are much centralized, and thereby the user capacity is considerably large, wherein the user capacity is associated with number of users and quality of service (Qos) required by the users. The more number of the users is, the higher request for Qos becomes, so that the cell is required to provide larger user capacity. The cell where the users are centralized is regarded as a user hot spot district, in this district, new cell equipments are disposed to provide service to the users in the hot spot district, for example, the cell B, cell C, cell D and cell E are within the hot spot district, the main object of these cellulars is to increase the user capacity and provide more advanced interface technology. The cell A seamlessly covers this region and provides service to this region. Coverage of the hot spot is non-continuous. For convenience of differentiation, the cell A is called as a basic coverage cellular, the cell B, C, D and E as the hot spot cellular.
The user capacity in the hot spot district is various along with the time, for instance, in a large shopping mall, there are many users in daytime, fewer users in night. The user capacity in some hot spot districts is various due to events, for instance, in a stadium, there are many users when an athletic contest is held, fewer users in the rest time. If the cell base station within the hot spot district can work as usual when there is not any user capacity, a large amount of electric energy will be wasted, obviously it is contrary to the target of sustainable development. Accordingly, the cell equipments in the hot spot district may be closed if there is no user capacity, and thereby do not provide interface service; or may be switch oned if there is user capacity, and thereby start to provide interface service for the users via an air interface, so that the purpose of reducing energy consumption can be achieved.
On the cell equipments in the hot spot district, the operator sets some closing policies in advance. When satisfying condition for closing, the equipments of the hot spot cell will be automatically closed, and send message to the adjacent cellulars, informing that the hot spot cell is in a closed state.
After the cell equipments in the hot spot district are closed, the cell for providing basic coverage serves to the users in the present region. When the number of users within the hot spot district is increased, and the user capacity in the cell for providing the basic coverage is above a threshold, it is required to switch on the cell equipments in the hot spot district.
A method of switch on the base station is provided with a cell for providing basic coverage, which sends a instruction to the cell equipments in the hot spot district when the user capacity of this cell is above a certain threshold to allow the cell equipments in the hot spot district to access a stage of preparation, at this stage, the hot spot cell merely sends basic control information, such as reference information and synchronizing information, rather than provide service for the UE, so that the UE can not be selected for this cellular. In FIG. 3, the method is described as follows:
In 301 step: a basic coverage cell decides to switch onswitch on the hot spot cellular, sends an switch on request message to the hot spot cellular, including an instruction for directing the hot spot cell to access a preparation state.
If user capacity of the basic coverage cell increases to exceed a predetermined threshold, the hot spot coverage cell is required to share some user capacity together with the basic coverage cellular. However, not all of the hot spot cell can shall the user capacity. This is associated with position of users and position of the hot spot cellular, if there are a large amount of users near the hot spot cellular, by switch onswitch oning the hot spot cellular, the users can be switched into the hot spot cell such that the user capacity of the basic coverage cell will be decreased, by contrast, if there is no or fewer users near the hot spot cellular, by switch onswitch oning the hot spot cellular, the users will not be served by the hot spot cell such that the user capacity of the basic coverage cell can not be shared by the hot spot cellular. Therefore, the basic coverage cell needs to find out the hot spot cell enable to share the user capacity efficiently, so that the basic coverage cell will not allow the hot spot cell to access a work state, but access a preparation state.
In 302 step: the hot sport cell sends an switch onswitch on response message to the basic coverage cell to confirm receipt of the message of 301 step.
In 303 step: the hot spot cell starts to access the preparation state and sends down-link reference information.
In 304 step: the basic coverage cell is provided with the UE for measuring, and receives a measurement report from the UE. The basic coverage sends a measurement configuration message to a plurality or all of the UEs in a connecting manner, instructing the UE to measure the surrounding cellulars. The UE sends a measurement report to the basic coverage cellular, wherein the measurement report includes measurement results of the surrounding cellulars, such as the physical cell identification (PCI) measured by the UE, reference signal receiving power (RSRP), and reference signal receiving quality (RSRQ). The basic coverage cell analyses the measurement report send by the UE and then determines the number of the UE covered by the hot spot cellular. Each hot spot cell has only one PCI, depending on which the basic coverage cell can find out the corresponding hot spot cellular. If the RSRP or RSRQ of the hot spot cell corresponding to the PCI measured by the UE is above a certain threshold, it can be determined that the UE is covered by the hot spot cellular. If the UE covered by the hot spot cell is above the predetermined threshold, the basic coverage cell may determine that the hot spot cell should be switch on. If the UE covered by the hot spot cell is below the predetermined threshold, the basic coverage cell may determine that the hot spot cell should not be switch on
In accordance with the determination results mentioned above, the basic coverage cell sends an switch on message of the 305 step to the hot spot cell that should be switch oned, hereafter, the hot spot cell accesses the normal work state and thereby can serve to the UE. The hot spot cell can send a response message of the 306 step to the basic coverage cellular.
The basic coverage cell sends the switch off instruction of the 307 step to the hot spot cell that should be switch off. The hot spot cell may send the response message of the 308 step to the basic coverage cellular. Thereafter, the hot spot cell accesses the switch off state.
However, the above-mentioned technical solutions have disadvantages below:
When the cell equipments of the hot spot district access the preparation stage, control signaling power as transmitted is higher. If the UE is close to a transmit unit of the hot spot cell but far from the basic coverage cellular, the UE will be interfered intensively by the hot spot cellular, and furthermore it causes the UE can not receive the data and be failed in a radio link. The more the users are, the more the failure in the radio link is.
If the UE is closer to the transmit unit of the basic coverage cellular, the down-link signal received by the UE from the basic coverage cell is stronger. If the hot spot cell uses the same resources, signals transmitted by the hot spot cell will be interfered by the down-link signals transmitted by the basic coverage cell such that the UE can not detect the reference information transmitted by the hot spot cellular.
Therefore, it is necessary to provide an effective technical solution to solve the problems of degradation of the system performance and poor service quality presented when the hot spot cell is initiated.